Departments of1Mechanical Engineering and.
Departments of2Radiology and.
J Neurosurg. 2021 Jun 4;136(1):197-204. doi: 10.3171/2020.11.JNS203684. Print 2022 Jan 1.
Despite advancement of thrombectomy technologies for large-vessel occlusion (LVO) stroke and increased user experience, complete recanalization rates linger around 50%, and one-third of patients who have undergone successful recanalization still experience poor neurological outcomes. To enhance the understanding of the biomechanics and failure modes, the authors conducted an experimental analysis of the interaction of emboli/artery/devices in the first human brain test platform for LVO stroke described to date.
In 12 fresh human brains, 105 LVOs were recreated by embolizing engineered emboli analogs and recanalization was attempted using aspiration catheters and/or stent retrievers. The complex mechanical interaction between diverse emboli (elastic, stiff, and fragment prone), arteries (anterior and posterior circulation), and thrombectomy devices were observed, analyzed, and categorized. The authors systematically evaluated the recanalization process through failure modes and effects analysis, and they identified where and how thrombectomy devices fail and the impact of device failure.
The first-pass effect (34%), successful (71%), and complete (60%) recanalization rates in this model were consistent with those in the literature. Failure mode analysis of 184 passes with thrombectomy devices revealed the following. 1) Devices loaded the emboli with tensile forces leading to elongation and intravascular fragmentation. 2) In the presence of anterograde flow, small fragments embolize to the microcirculation and large fragments result in recurrent vessel occlusion. 3) Multiple passes are required due to recurrent (15%) and residual (73%) occlusions, or both (12%). 4) Residual emboli remained in small branching and perforating arteries in cases of alleged complete recanalization (28%). 5) Vacuum caused arterial collapse at physiological pressures (27%). 6) Device withdrawal caused arterial traction (41%), and severe traction provoked avulsion of perforating and small branching arteries.
Biomechanically superior thrombectomy technologies should prevent unrestrained tensional load on emboli, minimize intraluminal embolus fragmentation and release, improve device/embolus integration, recanalize small branching and perforating arteries, prevent arterial collapse, and minimize traction.
尽管血栓切除术技术在治疗大血管闭塞（LVO）性卒中方面取得了进展，术者经验也有所增加，但完全再通率仍徘徊在 50%左右，而且三分之一接受成功再通的患者仍存在不良神经结局。为了更深入地了解生物力学和失败模式，作者对迄今为止描述的首例 LVO 卒中人类脑测试平台中，栓塞/动脉/器械的相互作用进行了实验分析。
在 12 个新鲜的人脑标本中，通过栓塞工程化的模拟栓子来重现 105 个 LVO，并尝试使用抽吸导管和/或支架取栓器进行再通。观察、分析和分类了不同的栓塞物（弹性、刚性和易于碎裂的）、动脉（前循环和后循环）和血栓切除术器械之间复杂的机械相互作用。作者通过失效模式和影响分析系统地评估了再通过程，并确定了血栓切除术器械在哪里以及如何失效，以及器械失效的影响。
该模型的首次通过效应（34%）、成功再通率（71%）和完全再通率（60%）与文献报道的结果一致。对 184 次使用血栓切除术器械的失败模式分析显示：1）器械对栓塞物施加张力，导致其伸长和血管内碎裂。2）在正向血流存在的情况下，小碎片栓塞至微循环，而大碎片导致血管再闭塞。3）由于反复出现的（15%）和残余的（73%）闭塞，或两者都有（12%），需要多次通过。4）在所谓的完全再通病例中，残余栓塞物仍存在于小分支和穿支动脉中（28%）。5）在生理压力下，真空导致动脉塌陷（27%）。6）器械撤回导致动脉牵引（41%），严重的牵引会导致穿支和小分支动脉的撕脱。
生物力学性能优越的血栓切除术技术应防止对栓塞物施加无约束的张力，尽量减少管腔内栓塞物的碎裂和释放，改善器械/栓塞物的整合，再通小分支和穿支动脉，防止动脉塌陷，并尽量减少牵引。
